Akka wrote:
Larry and all other responders,

Thanks for all the advice. We learned a lot from it.

On the R12/R134a issue: too late. We converted from R12 to R134a years
ago, and the system was working fine with R134a for a long time -- now,
no longer. When we installed the last compressor (marked clearly
'R134a' all over it) last month, we evacuated the system and put in a
new dryer, a big accumulator, and of course, gas. The compressor comes
with oil in it, as does the gas, so we didn't add any more.

I thought when r134a came with PAG oil and POE is usually recomended
for marine use. Maybe I'm wrong ...


When we last charged the system, we had 140 psi on the high side, and
something below atmospheric pressure on the low side, when the system
was running and the plates were cold. When we closed the valve on the
high-pressure side, we got 150 psi on the high side and a full vacuum
on the low side. That was the day before the compressor blew. ...

150 pounds sounds real high to me. My system, a DC powered Tecumseh
compressor, runs at about 95 psi on the high side. This corresponds
to a temp about 20 degrees hotter than the cooling water.